1. FIELD OF THE INVENTION
This invention relates generally to reamers, and more particularly to an adjustable chamfering reamer for use in threading machines which has an inner reamer member adjustably carried in an outer reaming member such that the reaming surfaces can be selectively positioned relative to one another to chamfer the exterior and interior of the threaded end of pipe or conduit and which has a trip shoulder for activating the chaser holder of the threading head to release the chamfered piece upon completion of the threading and chamfering operation.
2. BRIEF DESCRIPTION OF THE PRIOR ART
Chamfering reamers are secured by an adjustable draw bar in the threading head member of a threading machine and chamfer the ends of a pipe or conduit to remove the burr from the inside or outside diameter of the pipe or conduit after it has been threaded.
Some reamers, such as those manufactured by Teledyne Landis Machine of Waynesboro, Pennsylvania have fixed reaming surfaces and are designed to chamfer the inside and outside diameter of the pipe or conduit simultaneously. This type of reamer has a fluted body forming longitudinal wings which have an integral rearwardly extending, flat-bottom, generally V-shaped groove in the front portion of each wing. The converging inner sides of the V-groove chamfer the material and the flat bottom of the V-groove serves as a stop bar during the threading operation by forceably contacting the end of the pipe or conduit sufficient to activate a trip release within the threading machine to release the chamfered piece.
Prior art reamers having fixed reaming surfaces frequently become worn and require replacement or re-grinding of the cutting surfaces. The suggested method of resharpening or grinding is to grind on the flat side of each wing. This seriously impairs the useful life of the reamer because it reduces the cross section of the wing and changes the geometry of the cutting edges. The thinner reworked wings are often broken because the outer side wall of the flat bottom V-shape is thin and has a vulnerable stress point. The flat bottom tripping surface of the V-groove does not provide a desirable relief angle, and results in chip build- up which often causes damage to the first threads or even tearing off the end of the pipe. The flat bottom tripping surface of the V-groove is perpendicular to the longitudinal axis, and will also often gouge or damage the end of the pipe or conduit when forcible contact is made during the tripping sequence.
Another common problem with chamfering reamers is the down-time or loss of production caused by the necessity of frequent replacement and re-setting of a new reamer to accommodate pipe or conduit having a different wall thickness.
Teledyne Landis Machine of Waynesboro, Pennsylvania at one time marketed a two-piece reamer designed to chamfer the inside and outside diameter of the pipe or conduit. The reamer had a truncated nose piece with reaming wings which was bolted onto the front of a fluted body to form a rearwardly extending, flat-bottom, generally V-shaped groove. The flat-bottom of the V-groove served as a stop bar during the threading operation by forceably contacting the end of the pipe or conduit sufficient to activate a trip release within the threading machine to release the chamfered piece. The flat bottom tripping surface of the V-groove was perpendicular to the longitudinal axis and did not provide a relief angle. The reaming surfaces were fixed, and the nose piece was not adjustably positioned relative to the fluted body.
Other two-piece reamers are known in the art. There are several patents which disclose reamers and cutting tools of various configuration.
German patent 25 18 187 discloses a manual two-piece deburring tool designed to be secured in a handle and held in the hand to simultaneously chamfer the inside and outside diameter of the pipe or conduit. The reamer has a toothed inner cutter which is carried in an outer cutter member with the teeth of the inner cutter member pointing into the gaps between the teeth of the outer cutter member to form a V-shaped groove with the cutter surfaces forming a sharp bottom V-groove. The tool would not be suitable for use in a threading machine and there is no provision of a tripping shoulder to activate a trip release within the threading machine.
Tyne, U.S. Pat. No. 2,188,584 discloses a reamer designed to chamfer the inside and outside diameter of the pipe or conduit. The reamer has a central body with slots which receive replaceable reamer blade inserts which are bolted into the front of the body by a central bolt and washer. The removable reamer insert blades each have an integral rearwardly extending, flat-bottom, generally V-shaped groove formed therein. The flat bottom of the V-groove serves as a stop surface to activate a trip release within the threading machine to release the chamfered piece. The flat bottom tripping surface of the V-groove is perpendicular to the longitudinal axis and does not provide a relief angle. The reaming surfaces are fixed, and not capable of being adjustably positioned relative to one another.
Christensen, U.S. Pat. No. 4,468,829 discloses manual two-piece cleaning and deburring tool designed to be held in the hand to clean and deburr spent cartridge cases. The tool has an inner member carried in an outer member with the forward ends of the inner and outer member forming a segmented V-shaped groove which will deburr the interior and exterior surfaces of a spent cartridge case when the cartridge case is rotated relative to the tool. This tool would not be suitable for use in a threading machine and there is no provision of a tripping shoulder to activate a trip release within the threading machine.
Phillips, U.S. Pat. No. 4,930,946 discloses a two-piece chamfering reamer having an inner body with a truncated conical forward end defined by circumferentially spaced longitudinal wings with a reaming surface on their exterior and a trip shoulder at their rearward end and an outer sleeve which is secured on the inner body. The outer sleeve has forwardly extending projections with inwardly angled reaming surfaces. When assembled, the reaming surfaces of the projections are in circumferential alignment with the wings and the inner body is not adjustably positioned relative to the outer sleeve.
The present invention is distinguished over the prior art in general, and these patents in particular by an adjustable chamfering reamer used in automated threading machines for reaming the ends of pipe or conduit. The adjustable chamfering reamer has an inner reamer insert adjustably installed within a generally cylindrical outer sleeve. The front of the outer sleeve has circumferentially spaced forwardly extending projections with a flat inwardly and rearwardly angled reaming surface and a trip shoulder at the bottom thereof. The inner reamer insert has a truncated conical forward end defined by a plurality of circumferentially spaced longitudinal wings extending rearwardly and outwardly from the forward end and the exterior of the wings are curved reaming surfaces. When assembled, the wings are positioned between the projections of the outer sleeve in alternating relation. When viewed from the side, the overlapped reaming surfaces and shoulders form a plurality of rearwardly extending flat-bottom V-shaped grooves. The inner reaming surfaces provide sufficient clearance to pass under the thread chaser to ream the inside of the pipe or conduit while the outer reaming surfaces of the projections pass between the chasers to ream the outside and provide a limit or trip shoulder. The width of the flat-bottom V-shaped groove can be adjustably altered by positioning the inner reamer insert relative to the outer sleeve to receive pipe or conduit of various wall thicknesses and to ream the exterior and interior diameters at the end of the pipe or conduit simultaneously.